Increase in lower-stratospheric water vapour at a mid-latitude Northern Hemisphere site from 1981 to 1994

Oltmans, S. J.; Hofmann, D. J.

doi:10.1038/374146a0

Cited by 229 publications

(133 citation statements)

References 25 publications

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“…In fact, negative or very small positive changes in water vapor are evident below 60 hPa (Fig. 2), while water vapor trends above are positive and on the order of 0.5 to 1%/year quoted in Oltmans and Hofmann (1995). Changes between 60 hPa and 100 hPa may very well reflect near tropical tropopause conditions and possible changes in dehydration processes in the polar vortices, especially in the Southern Hemisphere.…”

Section: Discussionmentioning

confidence: 94%

“…To explain a change in 2 Â CH 4 þ H 2 O in the middle and upper stratosphere, a change in the upward flux of either water or methane is needed. In vertical profiles of water vapor trends at Northern Hemisphere middle latitudes over a multi-decadal period (Rosenlof et al 2001;Oltmans et al 2000), small or negative trends are seen over several time periods at levels between 60 and 100 hPa. This is also evident at all latitudes over a much shorter time period from the HALOE calculation of linear changes (see Fig.…”

Section: Transport Changes Over the Uars Recordmentioning

confidence: 99%

“…Oltmans and Hofmann (1995) presented evidence for a significant increase in lower stratospheric water vapor at a middle latitude site in the Northern Hemisphere that had persisted for over a decade. Oltmans et al (2000) and Rosenlof et al (2000) extended the original study to examine Northern Hemisphere data for a longer period of time using data from multiple instruments. The conclusion was that an increase of the order of 1%/yr had persisted for the last 40-50 years at Northern Hemisphere midlatitudes.…”

Section: Introductionmentioning

confidence: 99%

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Transport Changes Inferred from HALOE Water and Methane Measurements.

Rosenlof

2002

Journal of the Meteorological Society of Japan

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Changes in water vapor and methane covering the period 1992 through April 2001 are discussed. Global increases in 2 Â CH 4 þ H 2 O are evident, however there is significant spatial structure at levels between 10 and 100 hPa. Anti-correlated decreases in methane and increases in water vapor are noted in the upper stratosphere; these are associated with a slowing of the mass flux into the upper stratosphere and a concomitant increase in residence time above 10 hPa. Increases greater than those due to the surface increase in methane are more difficult to explain. One possibility is changes in the water vapor flux into the middle and upper stratosphere associated with a widening of the tropical upwelling. Another possible cause is a change in the ratio of summer/winter net upwelling. Additionally, the first 3 years of the period considered appear anomalous at many levels simultaneously. It is postulated that this is due to enhanced vertical mixing at the start of the data record.

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Section: Discussionmentioning

confidence: 94%

Section: Transport Changes Over the Uars Recordmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Transport Changes Inferred from HALOE Water and Methane Measurements.

Rosenlof

2002

Journal of the Meteorological Society of Japan

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“…The interest in middle atmospheric H 2 O was further intensified following observations made by Oltmans and Hofmann (1995) and after this by others (SPARC, 2000, and references therein;Rosenlof et al, 2001) who found increasing H 2 O concentrations of 30-150 nmol/mol yr −1 in the middle atmosphere since 1954. Not only the possible causes of this trend but also the consequences for Earth's climate and the chemistry of the middle atmosphere are a matter of vital discussion Shine, 1999, 2002;Kirk-Davidoff et al, 1999;Stenke and Grewe, 2004;Röckmann et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

Modelling the budget of middle atmospheric water vapour isotopes

Zahn¹,

Franz

Bechtel

et al. 2006

Atmos. Chem. Phys.

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Abstract.A one-dimensional chemistry model is applied to study the stable hydrogen (D) and stable oxygen isotope ( 17 O, 18 O) composition of water vapour in stratosphere and mesosphere. In the troposphere, this isotope composition is determined by "physical" fractionation effects, that are phase changes (e.g. during cloud formation), diffusion processes (e.g. during evaporation from the ocean), and mixing of air masses. Due to these processes water vapour entering the stratosphere first shows isotope depletions in D/H relative to ocean water, which are ∼5 times of those in 18 In the stratosphere the known mass-independent fractionation (MIF) signal in O 3 is in a first step transferred to the NO x family and only in a second step to HO x and H 2 O. In contrast to CO 2 , O( 1 D) only plays a minor role in this MIF transfer. The major uncertainty in our calculation arises from poorly quantified isotope exchange reaction rate coefficients and kinetic isotope fractionation factors.

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“…Water vapor in the atmosphere is the key trace gas controlling weather and climate, and plays a central role in atmospheric chemistry, influencing the heterogeneous chemical reactions that destroy stratospheric ozone. An increase in water vapor could thus lead to greater ozone loss (17).…”

Section: ( ( ) )mentioning

confidence: 99%

Compositional Heterogeneity of Hailstones: Atmospheric Conditions and Possible Environmental Implications

Martínez‐Frías¹

2001

AMBIO: A Journal of the Human Environment

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Increase in lower-stratospheric water vapour at a mid-latitude Northern Hemisphere site from 1981 to 1994

Cited by 229 publications

References 25 publications

Transport Changes Inferred from HALOE Water and Methane Measurements.

Transport Changes Inferred from HALOE Water and Methane Measurements.

Modelling the budget of middle atmospheric water vapour isotopes

Compositional Heterogeneity of Hailstones: Atmospheric Conditions and Possible Environmental Implications

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